2,3,3,3-Tetrafluoropropene represented by the chemical formula CF3CF═CH2 (HFC-1234yf) and 1,3,3,3-tetrafluoropropene represented by the chemical formula CF3CH═CHF (HFC-1234ze) are both compounds that are useful as refrigerants, and have been receiving attention for use as constituents of refrigerants or mixed refrigerants that can be used as alternatives for chlorofluorocarbon.
In connection with these compounds, Non-Patent Literature (NPL) 1 listed below, for example, discloses an HFC-1234yf preparation method comprising a single step of subjecting a compound represented by CF3CF2CH2X (X is Cl or I) to a reaction with zinc in ethanol. However, this method is not preferable as an industrial-scale production method, since zinc is expensive and a large amount of waste is generated.
In addition to the above, the following patent literature, etc., discloses methods for producing HFC-1234yf. Patent Literature (PTL) 1 discloses a method comprising reacting chloromethyl tetrafluoropropanate with amine; Patent Literature 2 discloses a method comprising the thermal decomposition of 1-trifluoromethyl-1,2,2-trifluorocyclobutane; Patent Literature 3 discloses a method comprising reacting chlorotrifluoroethylene (CClF═CF2) and methyl fluoride (CH3F) in the presence of a Lewis acid such as SbF5; and Patent Literature 4 discloses a method comprising the thermal decomposition of tetrafluoroethylene (CF2═CF2) and chloromethane (CH3Cl). Non-Patent Literatures 2 and 3 listed below also disclose HFC-1234yf production methods.
These processes, however, are not considered to be effective for industrial purposes since the starting materials are difficult to produce and are not easily obtained, the reaction conditions are severe, the reaction reagents are expensive, the yield is low, etc.
As a method for producing HFC-1234ze, known methods include a method comprising dehydrofluorination of CF3CH2CHF2 (HFC-245fa) (see Patent Literatures 5 to 8); a method comprising dehydrofluorination of CF3CHFCH2F (HFC-245eb) (see Patent Literatures 9 to 10); a method comprising fluorination of CF3CH═CHCl (HCFC-1233zd) (Patent Literature 11); and the like. However, these processes need to be improved for industrial usage since the starting materials are difficult to produce and are not easily obtained, the yield is low, multi-stage steps are required, etc.